METHOD FOR PRODUCING MONOTERPENE AND MONOTERPINOID COMPOUNDS AND USE THEREOF
In various embodiments, the present disclosure provides a method and enzyme for forming various compounds, such as monoterpenes and monoterpenoid compounds. In a specific example, the present disclosure provides a method for producing one or more of (−)-ipsdienol, (−)-ipsenol, ipsenone, and ipsdienone. The present disclosure also provides methods of using compounds formed from the disclosed method and enzyme.
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This application is a divisional of U.S. patent application Ser. No. 12/947,708, filed Nov. 17, 2009, which claims the benefit of U.S. Provisional Patent Application No. 61/115/623, filed Nov. 18, 2008, both of which are in incorporated herein by reference in their entirety.
STATEMENT OF GOVERNMENT SUPPORTThe invention was made with government support under grant numbers 0719279 and 0642182 awarded by the National Science Foundation. The government has certain rights in the invention.
FIELDThe present disclosure generally relates to a method for synthesizing monoterpenes and monoterpenoid compounds and a method for the use of such compounds. In a specific example, the present disclosure provides a method for producing one or more of (−)-ipsdienol, (−)-ipsenol, ipsenone, and ipsdienone.
BACKGROUNDMonoterpenes and related compounds (monoterpenoid alcohols, ketones, etc.) are a structurally diverse group of chemicals that share a common two-isoprene (2-methylbuta-1,3-diene) basic structure. They have broad uses industrially as solvents (e.g. turpentine) or as flavorants or scents. They are produced naturally mostly by plants: in the rinds of citrus fruits, or leaves of some species, or in the woody tissue of coniferous trees. For example, pine tree resin contains high monoterpene levels and is a major source of turpentine.
Some monoterpenes and monoterpenoids are chiral, that is, they have a “handedness.”Molecules that are structural “mirror images” of each other are called enantiomers. Enantiomers are usually referred to as “(+)” and “(−)”; “R” and “S”, or “D” and “L”. Although different enantiomers are chemically identical, then biochemical or physiological properties can be very different. For example, (+)-limonene has a citrus smell, while (−)-limonene smells like turpentine. A mixture of equal amounts of both enantiomers of a chiral compound is called a racemic mixture.
Pine bark beetles are closely linked to monoterpenes because they live in the phloem of pine trees, where they are exposed to and must deal with high monoterpene concentrations. Also, most species rely on monoterpenoid-based pheromonal communication to successfully attack a host tree. The enantiomeric composition of the pheromone blend is important. For example, the aggregation pheromone of western populations of Ips pini consists of ˜95% (−)-ipsdienol (2-methyl-6-methylene-2,7-octadien-4-ol) while a racemic mixture is not attractive at all. In contrast populations of I. pini from eastern North America use racemic ipsdienol as a pheromone. A related species endemic to the southeast U.S., I. calligraphus, is attracted to (−)-ipsdienol, but dispersed by (+)-ipsdienol.
There are a number of commercially important pine bark beetle species. For example, Ips calligraphus is distributed across mostly eastern North America. As mentioned above, I. calligraphus responds to (R)-(−)-ipsdienol. Like other scolytids, Ips spp. periodically cause loss of wood (cut wood and sometimes standing trees) over extensive areas. Their galleries do not affect the structural properties of the wood significantly, but may render it useless for veneer or furniture making. However, they tend to be less aggressive and less host-specific than Dendroctonus spp. They mostly breed in slash, or in broken, fallen or dying trees, but I. calligraphus can, under favorable, conditions make successful primary attacks on healthy Pinus stands.
I. calligraphus forms part of the so-called “southern pine bark beetle guild” (including also Dendroctonus frontalis, D. terebrans, I. grandicollis and I. avulsus), which attacks disturbed Pinus spp, in southeastern USA (e.g. disturbance by lightning strike, attacks by defoliating insects) and also causes economic problems by infesting freshly cut logs and pulpwood and introducing bluestain fungi. Published information on I. calligraphus as a pest relates almost exclusively to this area and to the Caribbean. It is considered only a secondary pest in California. Subsp. ponderosae, though reportedly widespread in western USA, is not considered as a pest there.
Ips confusus is distributed across the western US. I. confusus infests pinyon pine trees and causes periodic, severe, widespread damage. This species responds to (+)-ipsdienol and ipsenol. They mostly breed in slash, or in broken, fallen or drying trees. In this way, I. confusus can kill pinyon pines in southwest USA, when outbreaks start on trees that are damaged or uprooted in land-clearance schemes. I. paraconfusus is of greater practical importance because it attacks the timber tree P. ponderosa, killing saplings and young trees up to about 65 cm in diameter. Outbreaks develop on recently cut wood and spread to nearby living trees. This is reflected by a much greater number of publications on I. paraconfusus than on I. confusus. Top-killing by I. paraconfusus can contribute to outbreaks of the more dangerous pest Dendrocionus brevicomis.
Ips typographus is distributed across northern Europe and Asia. This species responds to ipsenol as an anti-aggregation pheromone. I. typographus is the most destructive species of the genus Ips, and probably the most serious pest on spruce in Europe. There are records of outbreaks dating from the eighteenth century. Those outbreaks resulted in the loss of million of cubic meters of wood.
SUMMARYRepresentative embodiments of the present disclosure are described in the appended claims. There are additional features and advantages of the various embodiments of the present disclosure. They will become evident from the following disclosure.
In this regard, it is to be understood that the appended claims are a brief summary of the various embodiments described herein. Any given embodiment of the present disclosure need not provide all features noted above, nor must it solve all problems or address ail issues in the prior art noted above.
Unless otherwise explained, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In case of conflict, the present specification, including explanations of terms, will control. The singular terms “a,” “an,” and “the” include plural referents unless context clearly indicates otherwise. Similarly, the word “or” is intended to include “and” unless the context clearly indicates otherwise. The term “comprising” means “including;” hence, “comprising A or B” means including A or B, as well as A and B together. All numerical ranges given herein include all values, including end points (unless specifically excluded) and any and all intermediate ranges between the endpoints.
Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, suitable methods and materials are described herein. The disclosed materials, methods, and examples are illustrative only and not intended to be limiting.
In one aspect, the present disclosure provides a polynucleotide, such as a cDNA or a RNA, and its encoded enzyme, collectively referred to herein as “Ipi12D04.” Ipi12D04 is also intended to embrace modified polynucleotides and polynucleotide fragments based on, similar to, or related to, Ipi12D04 that encode enzymes which exhibit oxidase or reductase activity, such as those capable of acting on at least some of me substrates as native Ipi12D04 enzyme. Ipi12D04 is also intended to embrace the enzymes produced by such modified polynucleotides or polynucleotide fragments. The Ipi12D04 enzyme can be used in various tonus, including crude cell extracts, isolated enzyme, or purified enzyme. In some eases, the Ipi12D04 enzyme is produced by a transgenic host cell into which an Ipi12D04 polynucleotide has been introduced. In other cases, the Ipi12D04 enzyme is synthetically produced. The Ipi12D04 enzyme, in another implementation, is isolated, such as from an organism.
In a specific embodiment, a cDNA of the present disclosure was identified from an expressed sequence tag clone generated from Ips pini c-DNA library plate #012, clone D04. The associated gene is encoded in the genome of the pine engraver, Ips pini, a bark beetle that has a host range across most of North America. The cDNA sequence was determined to be the sequence shown below in SEQ ID NO: 1:
The full-length cDNA is 843 nucleotides long and includes a 762 nucleotide open reading frame.
The Ipi12D04 enzyme encoded by the Ipi12D04 c-DNA appears to be to natively “tune” the enantiomeric composition of male-produced ipsdienol: Myrcene is first converted to ˜80%:20% (−)-:(+)-ipsdienol by a cytochrome P450 (CYP9T2), Ipi12D04 then, apparently acts on the (+)-enantiomer, first oxidizing it to ipsdienone, and then reducing the ketone stereo-specifically to (−)-ipsdienol. A schematic diagram of this process is illustrated in
The present disclosure thus provides a method of producing the Ipi12D04 enzyme. In one example, the method includes producing transgenic cells, such as insect cells, with the Ipi12D04 cDNA. The transformed cells express the Ipi12D04 enzyme, which can then be isolated and purified.
Ipi12D04 enzyme can be used to stereospecifically interconvert various monoterpines and monoterpinoids, including ipsdienol, ipsenol, ipsdienone, and ipsenone. For example, Ipi12D04 enzyme can be used to convert ipsenone stereospecifically to (−)-ipsenol. Ipi12D04 enzyme can also be used to convert ipsdienone stereospecifically to (−)-ipsdienol, Ipi12.D04 enzyme can be used to convert ipsensol or ipsdienol to the corresponding ketone. The ketones, as explained above, can then be sterospecifically converted to (−)-alcohol using Ipi12D04 enzyme.
In some examples of the method of the present disclosure, a compound produced by the action of Ipi12D04, including one or more of (−)-ipsdienol, (−)-ipsenol, ipsdienone, or ipsenone produced using Ipi12D04 is used in an insect control composition. These substances may be mixed with other compounds, including attractants, dispersants, or insecticides. For example, the substances may be mixed with other semiochemicals to tune a composition to a desired function, such as attracting or dispersing a particular insect species. In a more particular example, (−)-ipsdienol is mixed with one or more of (+)-ipsdienol, (−)-ipsenol, (+)-ipsenol, ipsdienone, or ipsenone. In another example, (−)-ipsenol is mixed with one or more of (+)-ipsenol, (−)-ipsdienol, (+)-ipsdienol, ipsdienone, or ipsenone. According to a more particular method, a pheromone blend of a particular insect species, such as a bark beetle species, is created using one or more of (−)-ipsdienol, (−)-ipsenol, ipsenone, or ipsdienone produced using Ipi12D04. Suitable insecticides include, without limitation, pyrethrin or pyrethroid toxins, which may be natural or synthetic, esfenvalerate, malathion, dimethoate, bifenthrin, and O,O-dimethyl O-(2,4,5-trichlorophenyl)-phosphoro-thioate; zetacypermethrin, and mixtures thereof.
The disclosed compositions may include additional ingredients, including those used to promote dispersion, stability, or efficacy. For example, ingredients can be used to control the release rate of the active agent or agents.
The present disclosure also provides devices for dispersing a composition according to the present disclosure or devices to which a composition of the present disclosure has been applied. For example, a composition of the present disclosure may be manufactured in a spray bottle or spray can. When the composition is used as a dispersant the composition may be dispensed on or proximate items to be protected, such as trees or fallen logs. When used as an attractant, the composition is, in one example, placed at location sufficiently remote from items to be protected, such as timber stands, fallen logs, or lumber piles. Alternatively or additionally, the composition may be mixed with, or placed proximate to, insecticidal compositions or used to lure insects into a physical trap. Attractant compositions may also be used in order to assist in monitoring insect populations.
The composition may be placed m a suitable trap or other device. For example, the composition may be placed in a suitable device, such as a bubble gap, having a permeable barrier through which the composition may be released. The composition may also be impregnated into various materials, including polymers, hydrogels, microbeads, clays, rubber, or cellulose.
The proper semiochemlcal mixture needed to attract or disperse a particular species, as well as the amount of a particular composition to be used for a particular application, is within the skill of the ordinary art worker to determine, including using empirical methods.
In another aspect, the present disclosure provides transgenic cells into which an Ipi12D04 polynucleotide has been inserted. The present disclosure also provides for enzymes expressed by such transgenic cells. In yet another aspect, the present disclosure provides compounds produced by the action of such enzymes on a substrate. Additional aspects of the present disclosure are described in the appended claims.
EXAMPLEIpi12D04 function was determined by assays of recombinant protein expressed in a baculoviral system using Sf9 cells. The Ips pini 12D04 ORF was amplified from the expressed sequencing tag (EST) clone, 12D04 in pDONR222 by PCR with forward and reverse primers, 12D04F3 and 12D04R5 (Table 1). The amplification product was cloned into the EcoRI site of pENTR4 (Invitrogen) (modified to remove the NcoI site in the poly-linker (Sandstrom et al., Functional expression of a bark beetle cytochrome P450 that hydroxylates myrcene to ipsdienol. Insect Biochem Mol Biol 36. 835-45 (2006)) (
Invitrogen has detailed protocols for the growth and maintenance of Sf9 cells, recombinant baculovirus construction, and heterologous expression using the BaculoDirect™ Expression Kit. Briefly, an LR recombination reaction transferred the 12D04 ORF from the pENTR4 construct into the BaculoDirect™ Linear DNA and created the recombinant baculoviral 12D04 clone. This construct was transfected into Sf9 cells and grown in the presence of ganciclovir for negative selection against non-recombinant virus. High titer P3 viral stocks were created by successive 72 hour amplifications of the initial (P1) and P2 viral stocks. Plaque assays were performed on the P2 and P3 virus stocks to establish the viral titters. A P3 viral stock multiplicity of infection (MOI, pfu/cell) of 8 was used to infect Sf9 cells grown at a density of 1.0×106 cells/ml in a disposable 250 ml shaker flask.
Infected Sf9 cells were grown for 72 hours before the culture media, containing the recombinant I2D04 protein, was isolated. Briefly, cells were pelleted by centrifugation at 3000 g at 4° C. for 10 minutes. The supernatant was collected and cells were discarded.
Recombinant protein production was established by western blot using 1: 1,000 Anti-12D04 primary antibody (GenScript), 1:5,000 Goat Anti-Rabbit secondary andbody (Biorad, Hercules, Calif.) and SuperSignal West Pico Chemiluminescent Substrate (Pierce, Rockford, Ill.).
An affinity-purified polyclonal antibody (rabbit) for 12D4 was produced for our work by GenScript Corporations. The peptide sequence (see below) was designed from the Ips pini 12D04 amino acid sequence by Genscript with some modifications we suggested.
Enzyme activity is determined by a pyridine nucleotide (PN) binding assay that monitors production or consumption of NADH/NADPH by measuring the absorbance of the catalysts reaction at 340 nm using a spectrophotometer. The reactions include reaction buffer (0.1 M NaP pH 7.8 and 1.1 mM EDTA), enzyme, PN, and substrate (monoterpene) in a 1 ml total volume and the absorbance was measured over time at room temperature. The volatiles produced from the reactions were extracted three times with pentane:ether (1:1) spiked with 200n g/ml n-octanol (internal standard) and concentrated to approximately 100 ul with nitrogen gas. The samples were directly analyzed by coupled GC-MS at the Nevada Proteomics Center at UNR.
Enzyme activity was determined by a pyridine nucleotide (PN) binding assay that monitored production or consumption of NADH/NADPH spectrophotometrically. The reaction mixture included reaction buffer (0.1 M NaP pH 7.8 and 1.1 mM EDTA), enzyme, PN, and substrate (monoterpene) in a 1 ml total volume. The absorbance was measured over time at room temperature. The reactions were extracted three times with pentane:ether (1:1) spiked with 200 ng/ml n-octanol (internal standard) to extract monoterpenoids and concentrated to approximately 100 ul with nitrogen gas. The samples were directly analyzed by coupled GC-MS at the Nevada Proteomics Center at UNR.
Biochemical reactions catalyzed by recombinant Ipi12D04, as determined by functional assays, are summarized below, in general, the enzyme functions as an oxidoreductase, using NAD(P) or NAD(P)H as cofactors, depending on whether it is oxidizing or reducing a substrate. Biochemical evidence (gas chromatographs, mass specta) supporting these activities is provided in
The action of Ipi12DO4 enzyme on ipsdienone was also studied.
It is expected that Ipi12D04 enzyme will convert any mixture of ipsdienol enantiomers into (−)-ipsdienol if the enzyme is incubated with both NAD(P) and NAD(P)H. The oxidation step may be stereo-selective for (+)-ipsdienol as a substrate. Similarly, (+)-ipsenol should be readily converted to (−)-ipsenol in a similar manner.
It is to be understood that the above discussion provides a detailed description of various embodiments. The above descriptions will enable those of ordinary skill in the art to make and use the disclosed embodiments, and to make departures from the particular examples described above to provide embodiments of the methods and apparatuses constructed in accordance with the present disclosure. The embodiments are illustrative, and not intended to limit the scope of the present disclosure. The scope of the present disclosure is rather to be determined by the scope of the claims as issued and equivalents thereto.
Claims
1. An isolated, synthetic, or transgenically expressed polypeptide having oxidation reduction or oxidoreductase activity encoded by a polynucleotide sequence at least 95% homologous to the sequence of SEQ ID NO:1.
2. The polypeptide of claim 1, wherein the polynucleotide sequence is at least about 99% homologous to the sequence of SEQ ID NO:1.
3. The polypeptide of claim 1, wherein the polynucleotide sequence is the sequence of SEQ ID NO:1.
4. A polypeptide encoded by a fragment of a polynucleotide sequence at least 95% homologous to the sequence of SEQ ID NO:1.
5. A method of catalyzing the oxidation of ipsenol or ipsdienol comprising contacting a sample comprising ipsenol or ipsdienol with the polypeptide of claim 1.
6. A method of catalyzing the reduction of ipsenone or ipsdienone comprising contacting a sample comprising ipsenone or ipsdienone with the polypeptide of claim 1.
7. A process for resolving an enatiomeric mixture of ipsenol or ipsdienone comprising:
- providing an enzymatically active polypeptide of claim 1;
- providing a mixture comprising at least one of ipsenol or ipsdienol;
- contacting the mixture with the polypeptide under conditions wherein the polypeptide can oxidize the alcohol;
- contacting the mixture with the polypeptide under conditions wherein the polypeptide can reduce the previously oxidized alcohol; and
- recovering a mixture of alcohols enriched in one enantiomer or a mixture of alcohols enriched in the opposite enantiomer.
8. An assay for identifying a functional polypeptide of claim 1 that retains oxidation or reduction activity, the assay comprising:
- contacting the polypeptide with a substrate molecule under conditions which allow the polypeptide to function; and
- detecting either a decrease in the level of the substrate or an increase in the level of the specific reaction product of the reaction between the polypeptide and the substrate, wherein a decrease in the level of substrate or an increase in the level of the reaction product indicates a functional polypeptide.
Type: Application
Filed: Feb 25, 2013
Publication Date: Sep 5, 2013
Patent Grant number: 8945890
Applicant: Board of Regents of the Nevada System of Higher Education, on Behalf of the University of Nevada, (Reno, NV)
Inventors: Claus Tittiger (Reno, NV), Rubi Figueroa-Teran (Reno, NV), Gary J. Blomquist (Sparks, NV)
Application Number: 13/775,860
International Classification: C12P 7/04 (20060101);